PMID- 33527151
OWN - NLM
STAT- MEDLINE
DCOM- 20210802
LR  - 20210802
IS  - 1432-2307 (Electronic)
IS  - 0945-6317 (Linking)
VI  - 479
IP  - 1
DP  - 2021 Jul
TI  - Assessment of HER2 using the 2018 ASCO/CAP guideline update for invasive breast 
      cancer: a critical look at cases classified as HER2 2+ by immunohistochemistry.
PG  - 23-31
LID - 10.1007/s00428-021-03034-4 [doi]
AB  - In 2018, the American Society of Clinical Oncology/College of American 
      Pathologists revised the criteria for HER2 immunohistochemistry (IHC) equivocal 
      (2+) classification in their updated guideline. We reviewed invasive breast 
      cancer specimens originally classified as equivocal (2+) under the 2018 guideline 
      that underwent HER2 fluorescence in situ hybridization (FISH) testing from August 
      2018 to August 2019 at our Canadian reference hospital to investigate cases with 
      ambiguous staining patterns between the 1+ and 2+ definitions. Demographics, 
      pathologic features, and pre-analytic conditions were recorded. The H&E and 
      corresponding HER2 IHC slides were reviewed to confirm tumor type and grade, and 
      classify as HER2 indeterminate, 0, 1+, 2+, or "Intermediate" (staining features 
      between the 1+ and 2+ classifications). FISH testing was performed on 289 cases 
      and 273 met inclusion criteria. The FISH-amplified rate was 12.1%. Upon IHC 
      review, 44.7% (122/273) of cases were reclassified as Intermediate. These cases 
      had incomplete staining with moderate intensity (43/122, 35.3%) and/or <10% 
      complete weak or moderate staining (102/122, 83.6%). Intermediate cases had a 
      significantly lower frequency of amplified FISH results than 2+ cases (p < 
      0.0001), with only four (3.3%) FISH positive and two (1.6%) FISH heterogeneous. 
      Our study highlights the ambiguity in the current guideline for classifying some 
      HER2 IHC patterns. As the rate of gene amplification in these cases was low 
      (4.9%), we recommend adhering to the 2018 HER2 2+ criteria for reflex FISH 
      testing. However, cases with <10% moderate complete staining and certain 
      heterogeneous patterns warrant special consideration. Further descriptive 
      clarification of 1+ criteria is needed.
CI  - (c) 2021. The Author(s), under exclusive licence to Springer-Verlag GmbH, DE part 
      of Springer Nature.
FAU - Taylor, Valerie J
AU  - Taylor VJ
AD  - Department of Pathology and Laboratory Medicine, Dalhousie University, Halifax, 
      NS, Canada.
FAU - Barnes, Penny J
AU  - Barnes PJ
AD  - Department of Pathology and Laboratory Medicine, Dalhousie University, Halifax, 
      NS, Canada.
AD  - Nova Scotia Health Authority, Halifax, NS, Canada.
FAU - Godwin, Sean C
AU  - Godwin SC
AD  - Department of Biology, Dalhousie University, Halifax, NS, Canada.
FAU - Bethune, Gillian C
AU  - Bethune GC
AUID- ORCID: 0000-0001-9147-759X
AD  - Department of Pathology and Laboratory Medicine, Dalhousie University, Halifax, 
      NS, Canada. Gillian.Bethune@nshealth.ca.
AD  - Nova Scotia Health Authority, Halifax, NS, Canada. Gillian.Bethune@nshealth.ca.
LA  - eng
PT  - Journal Article
DEP - 20210201
PL  - Germany
TA  - Virchows Arch
JT  - Virchows Archiv : an international journal of pathology
JID - 9423843
RN  - 0 (Biomarkers, Tumor)
RN  - EC 2.7.10.1 (ERBB2 protein, human)
RN  - EC 2.7.10.1 (Receptor, ErbB-2)
SB  - IM
MH  - Adult
MH  - Aged
MH  - Aged, 80 and over
MH  - Biomarkers, Tumor/*analysis/genetics
MH  - Breast Neoplasms/*enzymology/genetics/pathology
MH  - Female
MH  - Gene Amplification
MH  - Humans
MH  - *Immunohistochemistry
MH  - *In Situ Hybridization, Fluorescence
MH  - Middle Aged
MH  - Neoplasm Grading
MH  - Neoplasm Invasiveness
MH  - Predictive Value of Tests
MH  - Receptor, ErbB-2/*analysis/genetics
OTO - NOTNLM
OT  - ASCO/CAP guidelines
OT  - Equivocal
OT  - HER2 immunohistochemistry
OT  - HER2 testing
OT  - Invasive breast cancer
EDAT- 2021/02/03 06:00
MHDA- 2021/08/03 06:00
CRDT- 2021/02/02 06:12
PHST- 2020/09/15 00:00 [received]
PHST- 2021/01/13 00:00 [accepted]
PHST- 2021/01/08 00:00 [revised]
PHST- 2021/02/03 06:00 [pubmed]
PHST- 2021/08/03 06:00 [medline]
PHST- 2021/02/02 06:12 [entrez]
AID - 10.1007/s00428-021-03034-4 [pii]
AID - 10.1007/s00428-021-03034-4 [doi]
PST - ppublish
SO  - Virchows Arch. 2021 Jul;479(1):23-31. doi: 10.1007/s00428-021-03034-4. Epub 2021 
      Feb 1.